The only solution I see to this (but of course I don’t know your whole scenario, so it may not be applicable) is to keep a count in the event where you update the visibility of DataRows. Increase or decrease the count for each row you set the Visible property to true or false, accordingly. In doing that, your count will always be the actual count of visible rows.
You can use the Tag property on the ParentGroup to store and update this value for each group.
Imported from legacy forums. Posted by André (had 1874 views)